Do i have a bad lifepo4 battery?

[Darren67-72]

Do I have a bad lifepo4 battery?
System; growatt 8000mpv dmv (same as 12000) 6 lifepower4 batteries in Signature Solar rack. Batteries connected in diagonal orientation. Currently using use2 programming as suggested by S.S. BUT, I have increased the cut off voltage, changed from 46v to 47v this is important for this discussion.
Pv= 4600w of 9200 total
Charge- 58v
Float- 56.5v
Cut out- 47v
I've been running this system for about a month.

Issue:
When the batteries get low, after several days of cloudy weather, one battery will turn off. (The same battery) it had been running a little behind, according to soc lights.
My first attempt to fix the issue was to top balance the batteries. This did balance all the battery soc lights. They stayed in synch after that. This is where I changed the cut out voltage from 46v to 47v thinking it would not drive the batteries so close to bms turn off power.
This morning I check on the system, expecting that my batteries would run low, due to very cloudy weather.
I have an error 61, (battery imballance out by more then 0.5v) and the same battery is off.
Question 1: how does the inverter know there is a battery imbalance, with no communication?
Question 2: how could there be a VOLTAGE imbalance when they are wired to a bus bar. Wouldn't they keep voltage equal?
My assumption would be; I either have a bad battery (or BMS in said battery ) OR I need to top balance, again.

I'm thinking of changing back to communications setting. ???
https://diysolarforum.com/threads/do-i-have-a-bad-lifepo4-battery.43533/reply?quote=549406
I'd like to add, this issue appears similar to Robby's . Any thoughts?

 

[Don B. Cilly]

Hard to tell, but 47V is way too low.
-

 

[Darren67-72]

47v cut out? Back to grid. Seems really safe?

 

[Darren67-72]

Signature solar, said to set at 46v...

 

[Don B. Cilly]

 

[MisterSandals]

Batteries connected in diagonal orientation

Can you post a pic of how you have these wired? 6x 48V in diagonal sounds a little odd and perhaps difficult to do in the most optimal manner.

 

[Darren67-72]

I could, but... I'm using a signature solar cabinet and have the positive cable attached at the top left on bus bar and negative attached at the bottom right to the (negative) bus bar. As Will suggested in his video.

 

[Brett V]

56.5 float point seems high to me...

 

[Darren67-72]

Agreed, changed to 54.4 (per Will suggestions)

 

[Sunshine22]

Do I have a bad lifepo4 battery?
System; growatt 8000mpv dmv (same as 12000) 6 lifepower4 batteries in Signature Solar rack. Batteries connected in diagonal orientation. Currently using use2 programming as suggested by S.S. BUT, I have increased the cut off voltage, changed from 46v to 47v this is important for this discussion.
Pv= 4600w of 9200 total
Charge- 58v
Float- 56.5v
Cut out- 47v
I've been running this system for about a month.

Issue:
When the batteries get low, after several days of cloudy weather, one battery will turn off. (The same battery) it had been running a little behind, according to soc lights.
My first attempt to fix the issue was to top balance the batteries. This did balance all the battery soc lights. They stayed in synch after that. This is where I changed the cut out voltage from 46v to 47v thinking it would not drive the batteries so close to bms turn off power.
This morning I check on the system, expecting that my batteries would run low, due to very cloudy weather.
I have an error 61, (battery imballance out by more then 0.5v) and the same battery is off.
Question 1: how does the inverter know there is a battery imbalance, with no communication?
Question 2: how could there be a VOLTAGE imbalance when they are wired to a bus bar. Wouldn't they keep voltage equal?
My assumption would be; I either have a bad battery (or BMS in said battery ) OR I need to top balance, again.

I'm thinking of changing back to communications setting. ???
https://diysolarforum.com/threads/do-i-have-a-bad-lifepo4-battery.43533/reply?quote=549406
I'd like to add, this issue appears similar to Robby's . Any thoughts?

Did you ever get this figured out?

 

[Darren67-72]

Oh, I'm sorry.... I never finished the end results.
While using the USE or USE2 setting, if you deplete the battery bank to say... 47 or maybe 48 ish (nobody knows, as batteries can differ) one battery or even one cell can run too low and the bms will shut off the battery.
After a much needed firmware update and charging my system back to the communication setting, this has never been an issue again.